Ammunition



Oct. 18, 1960 I. R. BARR AMMUNITION Filed March 3, 1955 INVENTOR.

IRWIN R. BARR XTTORNEY United States Patent AMlVIUNITION Irwin R. Barr, Kingsville, Md., assignor to Aircraft Armaments, Inc., Baltimore, Md., a corporation of Maryland Filed Mar. 3, 1955, Ser. No. 491,959

1 Claim. (Cl. 102-38) This invention relates to ammunition for automatic guns, and particularly to ammunition having a foreshortened configuration for use in machine guns having high cyclic rates.

In a conventional machine gun using a reciprocating bolt, the basic time cycle is determined by the length of the ammunition, which in turn fixes the length of the stroke of the bolt. Obviously, if the ammunition can be shortened, the length of the stroke and hence the time necessary to complete a cycle can be reduced. This, in turn, allows a significant increase in the firing rate of the gun without increasing the accelerations in the moving parts of the gun beyond the permissible limits.

It is possible to reduce the length of a round of ammunition by increasing the diameter of the case and telescoping the projectile into the case. This leads to difficulty, however, since only the nose of the projectile extends from the chamber into the barrel of the gun and the rear of the projectile i supported only by the propellant contained in the case. Consequently, there is no assurance that the projectile will be properly aligned when it enters the bore of the gun. It has previously been proposed to avoid this difiiculty by providing each round with a cylindrical element which acts as a segment of the barrel to provide guidance and a seal until the projectile has entered the bore. The barrel segment, however, increases the weight of the round significantly, so that the total weight of ammunition carried is considerably increased over that of conventional ammunition. This is a serious drawback since the principal use of guns having high firing rates is in aircraft, where weight limitations are severe.

The present invention proposes a method of providing a telescoped round having means for maintaining the projectile in alignment with the bore of the gun while the round is fired, so that the projectile may enter the bore in alignment even though the projectile is entirely sup- 1 orted by the case before firing.

It is the object of this invention, therefore, to provide a telescoped ammunition round for automatic guns having a high rate of fire.

It is another object of this invention to provide a telescoped round which eliminates the need for a disposable barrel segment to keep the projectile aligned when the round is fired.

It is a further object of this invention to provide a telescoped round, the weight of which is substantially the same as conventional ammunition.

Further objects will become apparent from the following description and the accompanying drawing.

In the drawing:

Figure 1 is a cross sectional view of the telescoped ammunition round contemplated by this invention in place in the chamber of the gun.

Figure 2 is a sectional view taken along line 2-2 of Figure 1.

In the drawing a round of ammunition 1 constructed in accordance with the present invention is shown in the chamber of a goal with the bolt 3 of the gun in position behind the round. A projectile 4 is contained within the case 5 with only the nose of the projectile extending into the bore 6 of the gun. The case 5 is of sufficient diameter to contain the required quantity of propellant 7 and the forward edge 8 of the case serves to support the nose of the projectile at the rotating band 9. The bottom of the casing is centrally thickened at 13 to form an apertured head to facilitate manufacture of the means to be described presently which supports the rear of the projectile. Inserted and held in the usual manner within the aperture in head 13 is primer assembly holder 17 having on one face a recess 16 into which a primer assembly can be pressed, and on the opposite face, a solid, rod-like projection extending into an opening 11 formed in the rear of the projectile. Surrounding the connection between projection 10 and the part of holder 17 containing aperture 16, are vent means 15 which interconnect recess 16 with propellant 7.

Projection 10 is axially located within casing 5 and has a diameter that is small in comparison to its length, and extends into casing 5 a sufficient depth to cooperate with opening 11 to support, guide and center projectile 4 in bore 6 during its initial propulsion and until it has entered the same to a depth sufiicient to be supported thereby. By making holder 17 separate from casing 5, the ease in manufacturing a casing having an axially extending supporting projection attached thereto is apparent.

When the round is fired, the forward edge 8 of the case 5 is deflected into a peripheral groove 12 formed at the rear of the bore 6 and supports the nose of the projectile 4 until it has entered the bore. The projection 10 simultaneously supports the rear of the projectile and is of sufiicient length to keep the projectile aligned with the bore 6 until the projectile has traveled far enough into the bore to eliminate the necessity for further support.

Thus a round of ammunition is provided in which the projectile is supported entirely by the case in alignment with the bore of the gun both before and during the entry of the projectile into the bore, so that the overall length of the round need be only slightly longer than the length of the projectile itself while still providing any desired quantity of propellant. Although the round herein proposed incorporates a projectile having a conventional configuration, the total weight of the round is substantially equal to that of conventional rounds of the same caliber and containing the same charge, thereby providing a telescoped round which will allow the use of an extremely foreshortened bolt in a conventional gun mechanism, with the consequent higher rate of fire which such a configuration will allow.

Although but one embodiment of the round contemplated by this invention has been shown and described, it is obvious that many changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claim.

I claim:

A shortened round of ammunition comprising a tubular case open at one end and closed at the other, a projectile having a base portion and a nose portion, said projectile mounted in said case and being axially movable from a first position where said nose portion is supported by said open end and said base portion is adjacent to but spaced from said closed end, to a second position spaced from the first where said nose portion is within a gun bore and thereby supports said projectile against transverse movement during axial movement thereof, a projection attached to said closed end extending axially into said case, a portion on said projection of uniform crosssection and having a transverse dimension that is small in comparison to its axial dimension, aperture means with- Patented Oct. 18, 1960 in said base portion, a portion of said aperture means being of substantially the same cross-section and length as said projection portion and freely slidably engaged thereover throughout axial movement of said projectile between said two positions whereby said rear portion is supported and guided against transverse movement during such axial movement.

References Cited in the file of this patent FOREIGN PATENTS 

